Intraoperative Spinal Cord Monitoring Does Not Decrease New Postoperative Neurological Deficits in Patients With Cervical Radiculopathy or Spondylotic Myelopathy Undergoing One or Two Level Anterior Cervical Discectomy And Fusion

Abstract

Background: Intraoperative neurological monitoring (IONM) is commonly used in spine surgery. However, the utility of IONM in anterior cervical decompression and fusion (ACDF) remains a topic of debate. The purpose of the study was to investigate the utility and cost of IONM (both Somatosensory evoked potentials (SSEPs) and Motor Evoked Potentials (Tc-MEPs)) in reducing postoperative neurological deficits in myelopathic and non-myelopathic patients undergoing ACDF.

Methods: Retrospective chart review was performed to include only patients with cervical radiculopathy or myelopathy undergoing one or two level ACDF over a 7-year period at a busy academic center. SSEP and Tc-MEP tracings were reviewed for all monitored patients and significant changes and inconsistencies were noted. IONM billing codes (SSEP/Tc-MEP) were reviewed and summed to evaluate the average procedural cost. Medical records were reviewed for preoperative physical exam and for new postoperative neurological deficits on postoperative day one and again at six weeks and matched to the monitored tracings.

Results: There were 249 total patients (48 Non-monitored, 201 monitored). There was no difference in gender, age, or BMI between monitored and non-monitored groups. There was no difference in new neurological deficits in monitored compared with non-monitored patients with radiculopathy (p=0.1935) or myelopathy (p=0.1977). However, when radiculopathy and myelopathy patients were combined, there was an increased incidence of new neurologic deficits in monitored patients (8.0%) versus non-monitored patients (0%) (p=0.0830). All new neurological deficits occurred in patients with normal IONM tracings. There were no new neurologic deficits in the non-monitored radiculopathy or myelopathy groups. The average IONM procedure charge was $6500.

Conclusion: Our results indicate that intraoperative spinal cord monitoring did not reduce new neurological deficits in our cohort of patients. The higher incidence in new neurological deficits despite no IONM changes in our monitored group suggests a lack of utility of IONM in ACDF. Furthermore, at an average of $6500 per IONM procedure, the present study underlines the importance of prudence when choosing to use IONM in the era of cost containment.Level of Evidence: III.

Keywords: acdf; intraoperative spinal cord monitoring; postoperative neurological deficit.